Can 'Magic' Shoes Make You Happier By Changing the Sound of Your Footsteps?

Can these new "magic" shoes make you happier simply by changing the "soundtrack" of your body? A British research team claims that their "sonic shoes" make a person feel lighter and more confident simply by modifying the sound of the wearer's footsteps.

The experience of living in one's own body, and particularly the perception of its physical attributes, is extremely subjective, and able to be manipulated by all manner of external factors. For example, one famous experiment involved showing people a realistic-looking rubber hand, with their own hand hidden from view. When the subjects saw someone stroking the rubber hand, and felt someone rubbing their own hand in the same way, they began to perceive the rubber hand to be a part of their own body. This experiment demonstrates that our brains construct a model of our own body through bits and pieces of sensory input.

This team of researchers aims to take advantage of that same tendency, but using sound instead of tactile sensation. "Sound is a fundamental yet under-investigated dimension of body representations," says psychologist Manos Tsakiris at Royal Holloway, University of London. "For hearing people, there is a continuous, ever-present soundtrack to our bodily actions."

Ana Tajadura-Jiménez, a psychology researcher at University College London, has invented shoes that are fitted with microphones, and earphones for the wearer, which change the sounds of footsteps to higher-frequency tones. The mechanism by which they make the wearer feel lighter involves a theory of the brain called predictive coding. According to this theory, which is still being investigated by neuroscience researchers, the brain constructs predictions of the outcome of any given situation, and then constantly updates based on new experiences or changes to the parameters of the situation. In this case, the body expects to hear certain footstep sounds based on the size of the wearer's body, but instead hears the frequency of the footsteps of a much lighter person, causing the body to react as though it is, in fact, lighter.

"If the sensory feedback you get is not what you were expecting, you update your predictions," says Tajadura-Jiménez.

The research has not yet been published, but according to Tajadura-Jiménez, the results of her experiments involving sound manipulation techniques are all promising. For example, one of her studies purportedly showed that participants' estimation of their own waist size changed depending on their exposure to different types of sounds. Regarding the shoes specifically, Tajadura-Jiménez claimed that her research will show that people who try on the shoes report feeling happier, and that they consistently depict virtual avatars of themselves as skinnier after wearing the shoes. A New Scientist columnist tried on the shoes, and gave anecdotal support for the shoes' effectiveness:

"It is an unnerving experience. At first, I simply hear the unmodified sound of my footsteps. But then Tajadura-Jiménez filters the noise using an equaliser. Emphasising the higher frequencies mimics a lighter person's footsteps, causing them to sound higher-pitched, even slightly hollow. In a matter of seconds, I experience a sensation of lightness in my lower legs... Suddenly my lower legs feel lighter and longer. My knees feel looser, and I begin to raise them higher and higher as I walk. My walking speed increases until it's all I can do not to break into a trot. I feel slimmer, stronger, and full of energy. These are unlike any shoes I have ever worn."

They are now working on creating some kind of app that would allow consumers to feel this lightness on a regular basis by listening to the sound manipulation through their phones. This would likely be popular among runners and other athletes, but more importantly, Tajadura-Jiménez believes that sound manipulation could also assist in the treatment of various neurological and psychological diseases. In the case of chronic pain, sufferers' perception of their bodies is distorted by the experience of pain, so they think they are stretching more than they actually are during physical therapy exercises. If sound manipulation could give them real-time updates on their bodily movements, then their brains would be less likely to interpret the exercise as painful, and their physical therapy would be more effective. She also believes the shoes could specifically help to treat body dysmorphic disorder, the pathology that causes a mental distortion of the body in eating disorder sufferers. It would not be able to treat or "fix" the underlying problems that caused the eating disorder, but it could help manage certain symptoms on the way to recovery.

"We are finding that sound is affecting not just the perception of our body shape but our physical capabilities," she said. "Understand these sounds, and we could change our feelings in a positive way."